Plating apparatus and cleaning device used in the plating apparatus

ABSTRACT

A plating apparatus for plating a substrate is disclosed. The plating apparatus includes: a dip-type plating bath; a dry-type plating bath having a hole in a sidewall thereof; and a pressing mechanism configured to press a substrate holder, holding a substrate, against the sidewall of the dry-type plating bath to close the hole. The substrate holder includes a base member and a holding member configured to sandwich the substrate therebetween, a first seal portion configured to seal a gap between the substrate and the holding member, a second seal portion configured to seal a gap between the base member and the holding member, and a third seal portion configured to seal a gap between the holding member and the sidewall of the dry-type plating bath.

CROSS REFERENCE TO RELATED APPLICATION

This document claims priority to Japanese Patent Application Number 2013-207188 filed Oct. 2, 2013, the entire contents of which are hereby incorporated by reference.

BACKGROUND

It is a common practice in TAB (tape automated bonding) or flip chip to form protruding connection electrodes (i.e., bumps) of gold, copper, solder or nickel, or of multiple layers of such metals at predetermined portions (electrodes) of a surface of a semiconductor chip having interconnects formed therein so that the semiconductor chip can be electrically coupled via the bumps to substrate electrodes or TAB electrodes. There are various methods usable for forming the bumps, such as electroplating, vapor deposition, printing, and ball bumping. In recent years, electroplating, which can form fine bumps and can be performed in a relatively stable manner, has been widely used, as the number of I/O in a semiconductor chip increases and the electrode pitch becomes smaller.

Dip-type electroplating is one of typical electroplating methods. In this dip-type electroplating, a substrate is placed vertically in a plating bath and is immersed in a plating solution while the plating solution is supplied from a bottom of the plating bath to overflow it. A dip-type plating apparatus typically includes a substrate holder for holding the substrate in the vertical position. The substrate holder has a seal member for forming a hermetically closed space that surrounds a periphery of the substrate. Feeding electrodes are disposed in this hermetically closed space. The substrate is held by the substrate holder with a surface (to be plated) of the substrate exposed, and the substrate, together with the substrate holder, is immersed in the plating solution, so that the surface of the substrate is plated.

However, in such a dip-type plating apparatus, when the substrate holder is raised from the plating bath, the substrate holder carries the plating solution from the plating bath, thus reducing an amount of the plating solution in the plating bath. Particularly in a case of using an expensive plating solution, such as a gold plating solution, frequent refill of the plating solution results in an increase in cost. Further, in a case of performing multistage plating for different metals using a plurality of plating solutions, the plating solution, attached to the substrate holder, may be mixed into another plating solution in the next plating bath. As a result, several kinds of metals may be deposited on the substrate.

Moreover, if the plating solution remains on the substrate holder, the metal may be deposited on the substrate holder. Particularly, the gold plating solution has a property that gold is likely to be deposited. If a subsequent plating process is performed with the metal deposited on the seal member, the hermetically closed space may not be formed properly in the substrate holder, and the plating solution may possibly enter the hermetically closed space, thus contacting the feeding electrodes. Further, the deposited metal may hinder a movement of a movable part of the substrate holder. In order to prevent such metal deposition, it is necessary to perform cleaning of the substrate holder more frequently, resulting in an increase in an amount of cleaning liquid to be used and an increase in a cleaning time.

Under such circumstances, there is known a dry-type plating apparatus for plating a substrate by bringing only a surface to be plated of the substrate into contact with a plating solution (see Japanese laid-open patent publication No. 2004-353048 and Japanese laid-open patent publication No. 2000-192298, for example). A plating bath used in this dry-type plating apparatus has an opening in a sidewall thereof. A substrate holder is pressed against the sidewall of the plating bath so that the opening is closed with the substrate holder holding the substrate. In this state, a plating solution is supplied into the plating bath and then the substrate is plated with its surface, to be plated, in contact with the plating solution. Such a dry-type plating apparatus can minimize an area where the plating solution contacts the substrate holder. Therefore, it is possible to reduce the amount of the plating solution attached to the substrate holder.

However, the dry-type plating apparatus entails an installation space for a mechanism of pressing the substrate holder against the sidewall of the plating bath. Therefore, a footprint of the dry-type plating apparatus becomes larger than that of the dip-type plating apparatus.

Thus, there is proposed a plating apparatus employing a combination of a dry-type plating bath used in the dry-type plating apparatus and a dip-type plating bath used in the dip-type plating apparatus. The dip-type plating bath can relatively reduce the footprint thereof, while the dry-type plating bath can reduce the amount of the plating solution attached to the substrate holder. Therefore, the plating apparatus having such a configuration can reduce the amount of the plating solution attached to the substrate holder, without enlarging the footprint thereof.

However, since the dry-type plating bath and the dip-type plating bath have configurations significantly different from each other, the plating apparatus needs to be provided with two types of substrate holders for use in the dry-type plating bath and in the dip-type plating bath. When the multistage plating is performed on the substrate, the substrate is set in one of the two types of substrate holders and plated, and is then set in the other substrate holder and plated. Therefore, every time the substrate is transported between the dry-type plating bath and the dip-type plating bath, it is necessary to remove the substrate from one of the two types of substrate holders and set the substrate in the other substrate holder. These operations make it difficult to plate the substrate continuously.

As described above, the dry-type plating apparatus can reduce the amount of the plating solution attached to the substrate holder, but on the other hand, the plating solution may be attached to the sidewall of the plating bath that contacts the substrate holder. As a result, the metal may be deposited on the sidewall. Particularly, in the case of gold plating, the gold is liable to be deposited on the sidewall. If the metal is deposited on the sidewall, the opening of the sidewall is not closed in the subsequent plating process, and as a result the plating solution may possibly flow out to the exterior of the plating bath. Although it has been proposed to remove the metal by ejecting a cleaning liquid to the sidewall of the plating bath, it is difficult to remove the metal by the jet flow of the cleaning liquid.

SUMMARY OF THE INVENTION

According to an embodiment, there is provided a plating apparatus which can reduce a plating solution attached to a substrate holder without enlarging a footprint of the plating apparatus, and can plate the substrate continuously in multiple stages.

According to an embodiment, there is provided a cleaning device which can remove a metal deposited on a sidewall of a dry-type plating bath.

Embodiments, which will be described below, relate to a plating apparatus for plating a surface of a substrate, such as a wafer, and further relates to a cleaning device for cleaning a plating bath of the plating apparatus.

In an embodiment, there is provide a plating apparatus for plating a substrate, comprising: a substrate holder configured to hold the substrate; a dip-type plating bath configured to hold a first plating solution in which the substrate holder holding the substrate is immersed; a dry-type plating bath having a hole in a sidewall thereof and configured to hold a second plating solution; a transporter configured to transport the substrate holder to the dip-type plating bath and to a predetermined position beside the sidewall of the dry-type plating bath; and a pressing mechanism configured to press the substrate holder, holding the substrate, against the sidewall of the dry-type plating bath to thereby close the hole with the substrate holder holding the substrate, wherein the substrate holder includes a base member and a holding member configured to sandwich the substrate therebetween, a first seal portion configured to seal a gap between the substrate and the holding member, a second seal portion configured to seal a gap between the base member and the holding member, and a third seal portion configured to seal a gap between the holding member and the sidewall of the dry-type plating bath.

In an embodiment, the plating apparatus further comprises an electrical contact electrically connected to a plating power source, wherein the substrate holder includes a feeding terminal to be electrically connected to the substrate, and wherein the pressing mechanism is configured to press the substrate holder, holding the substrate, against the sidewall of the dry-type plating bath to close the hole with the substrate holder holding the substrate while pressing the feeding terminal against the electrical contact.

In an embodiment, the substrate holder includes a projecting surface projecting in a normal direction of the substrate, and a stepped portion provided outside of the projecting surface, and the third seal portion is provided on the stepped portion so that the third seal portion is pressed against the sidewall by the pressing mechanism.

In an embodiment, the projecting surface of the substrate holder lies in the same plane as an inner surface of the sidewall when the substrate holder is pressed against the sidewall.

In an embodiment, the first seal portion, the second seal portion, and the third seal portion are formed from a single seal member.

In an embodiment, the dry-type plating bath has an electrolyte chamber configured to hold an electrolyte, and a partition configured to isolate the second plating solution from the electrolyte, and an anode is disposed in the electrolyte chamber.

In an embodiment, the plating apparatus further comprises a cleaning device configured to clean the sidewall of the dry-type plating bath, wherein the cleaning device has substantially the same shape and size as those of the substrate holder, and wherein the transporter is configured to transport the cleaning device to the predetermined position beside the sidewall of the dry-type plating bath.

In an embodiment, the cleaning device includes a cleaning element configured to contact the sidewall of the dry-type plating bath, and a rotating mechanism configured to rotate the cleaning element on the sidewall.

In an embodiment, the plating apparatus further comprises a cleaning nozzle configured to supply a cleaning liquid to the cleaning element.

In an embodiment, the second plating solution comprises a gold plating solution.

In an embodiment, there is provide a cleaning device for use in a plating apparatus that includes (i) a substrate holder configured to hold a substrate, (ii) a dry-type plating bath having a hole in a sidewall thereof and configured to hold a plating solution, and (iii) a pressing mechanism configured to press the substrate holder, holding the substrate, against the sidewall of the dry-type plating bath to thereby close the hole with the substrate holder holding the substrate, the cleaning device comprising: a cleaning element configured to contact the sidewall of the dry-type plating bath; and a rotating mechanism configured to rotate the cleaning element on the sidewall of the dry-type plating bath, wherein the cleaning device has substantially the same shape and size as those of the substrate holder.

In an embodiment, the cleaning device further comprises a cleaning nozzle configured to supply a cleaning liquid to the cleaning element.

According to the embodiments described above, the plating apparatus includes the dip-type plating bath that can relatively reduce a footprint thereof, and the dry-type plating bath that can reduce an amount of the plating solution attached to the substrate holder. Further, the plating apparatus includes the substrate holder that can be used in both the dip-type plating bath and the dry-type plating bath. These configurations can reduce the plating solution attached to the substrate holder without enlarging the footprint of the plating apparatus, and can enable the plating apparatus to perform multistage plating on the substrate continuously.

Further, according to the embodiments described above, the cleaning element is rubbed against the sidewall of the plating bath to thereby remove the metal deposited on the sidewall of the plating bath.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view showing a plating apparatus according to an embodiment;

FIG. 2 is a perspective view showing a substrate holder;

FIG. 3 is a plan view showing the substrate holder shown in FIG. 2;

FIG. 4 is a right side view of the substrate holder shown in FIG. 2;

FIG. 5 is an enlarged view showing a part of the substrate holder shown in FIG. 4;

FIG. 6 is a schematic view showing a dip-type plating bath;

FIG. 7 is a schematic view showing a dry-type plating bath;

FIG. 8 is a view showing a part of the substrate holder pressed against a sidewall of the dry-type plating bath;

FIG. 9 is a view showing a drainage hole provided in a bottom of the substrate holder;

FIG. 10A is a view showing the substrate holder when hanging from a hanging base of the dry-type plating apparatus;

FIG. 10B is a view showing the substrate holder with its feeding terminal pressed against an electrical contact;

FIG. 11A is a view showing the substrate holder before hanging from a hanging base of the dip-type plating bath;

FIG. 11B is a view showing the substrate holder when hanging from the hanging base of the dip-type plating bath;

FIG. 12A is a view showing the substrate holder before hanging from the hanging base having an electrical contact on an upper surface thereof;

FIG. 12B is a view showing the substrate holder when hanging from the hanging base shown in FIG. 12A;

FIG. 13 is a plan view showing a cleaning device;

FIG. 14 is a cross-sectional view of the cleaning device;

FIG. 15 is a schematic view showing the cleaning device pressed against the sidewall of the dry-type plating bath;

FIG. 16 is a view comparing the length of the plating apparatus according to the embodiment to the length of a typical dry-type plating apparatus;

FIG. 17 is a view showing a modified example of the dry-type plating bath;

FIG. 18 is a view showing a drainage hole provided in a bottom of the substrate holder; and

FIG. 19 is an enlarged view showing a part enclosed by a symbol A shown in FIG. 17.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments will be described in detail with reference to the drawings. In FIGS. 1 to 19, identical or corresponding elements are denoted by the same reference numerals and duplicate descriptions thereof are omitted. FIG. 1 is a schematic plan view showing a plating apparatus according to an embodiment. As shown in FIG. 1, the plating apparatus includes an apparatus frame 1, two load ports 2 each receiving thereon a cassette in which substrates W, such as wafers, are stored, and a controller 3 configured to control operations of the plating apparatus. The plating apparatus further includes an aligner 4 for aligning a position of an orientation flat or a notch with a predetermined direction, a spin-rinse dryer (SRD) 6 for rotating a plated substrate W at a high speed to dry the substrate, a substrate holder opening-closing mechanism 24 for loading the substrate W onto a substrate holder 8 (see FIGS. 2 through 5) and unloading the substrate W from the substrate holder 8 by opening and closing the substrate holder 8, and a substrate transfer robot 22 for transporting the substrate W. The aligner 4, the spin-rinse dryer 6, the substrate holder opening-closing mechanism 24, and the substrate transfer robot 22 are arranged in the apparatus frame 1.

In the apparatus frame 1, there are disposed a storage container 30 for storing substrate holders 8 therein, a pre-cleaning bath 32 for pre-cleaning the substrate W, held by the substrate holder 8, with a cleaning liquid, such as pure water, and a pretreatment bath 33 for pretreating the substrate W with a pretreatment liquid. Adjacent to the pretreatment bath 33, there are disposed a first rinsing bath 40 for rinsing the pretreated substrate W with a rinsing liquid, and a plurality of dip-type plating baths 34 each for plating the substrate W. Each of the dip-type plating baths 34 is configured to hold therein a first plating solution in which the substrate holder 8 holding the substrate W is immersed. The first plating solution may be a plating solution, such as a copper plating solution, a nickel plating solution, or the like, which is relatively inexpensive and/or has a property that metal is relatively less likely to be deposited on the substrate holder 8 even if the plating solution is attached to the substrate holder 8.

Adjacent to the dip-type plating baths 34, there are disposed a second rinsing bath 41 for rinsing the plated substrate W with a rinsing liquid, and a plurality of dry-type plating baths 35 each for plating the substrate W. Each of the dry-type plating baths 35 is configured to hold a second plating solution therein. The second plating solution may be a plating solution, such as a gold plating solution, or the like, which is relatively expensive and/or has a property that metal is relatively likely to be deposited on the substrate holder 8 when the plating solution is attached to the substrate holder 8. Adjacent to the dry-type plating baths 35, there are disposed a third rinsing bath 42 for rinsing the plated substrate W with a rinsing liquid, and a blow cell 38 for removing the rinsing liquid from the substrate W and the substrate holder 8. The storage container 30 is configured to hold a plurality of substrate holders 8 in the vertical position and in parallel. The blow cell 38 is configured to remove droplets remaining on the surface of the substrate, held by the substrate holder 8, by ejecting N₂ gas or clean air to thereby dry the substrate.

The storage container 30, the pre-cleaning bath 32, the pretreatment bath 33, the first rinsing bath 40, the dip-type plating baths 34, the second rinsing bath 41, the dry-type plating baths 35, the third rinsing bath 42, and the blow cell 38 are arranged in series in accordance with the sequence of processes. These baths 32, 33, 34, 35, 38, 40, 41 and 42 constitute processing baths 50.

On the apparatus frame 1, there is provided a transporter 101 for transporting the substrate holder 8 together with the substrate W between the storage container 30, the processing baths 50, and the substrate holder opening-closing mechanism 24. The transporter 101 includes a fixed base 102 fixedly mounted to the apparatus frame 1 and extending in a horizontal direction, a lifter 103 configured to be movable on the fixing base 102 in the horizontal direction, and an arm 104 coupled to the lifter 103. The arm 104 has a gripper 111 for gripping the substrate holder 8. The arm 104 and the lifter 103 move together in the horizontal direction, and the arm 104 is lifted and lowered by the lifter 103. A drive source for moving the lifter 103 and the arm 104 in the horizontal direction can employ a linear motor, a rack-and-pinion, or a combination of a ball screw and a servomotor.

As shown in FIGS. 2 through 5, the substrate holder 8 includes a base member 54 having a rectangular plate shape, and a holding member 58 rotatably coupled to the base member 54 through a hinge 56 which allows the holding member 58 to open and close with respect to the base member 54. The substrate holder 8 holds the substrate W by sandwiching the substrate W between the base member 54 and the holding member 58. In another configuration, the holding member 58 may be disposed at a position opposite to the base member 54 so as to be opened and closed by moving the holding member 58 toward the base member 54 and away from the base member 54.

The base member 54 may be made of vinyl chloride. The holding member 58 includes a base portion 60 and an annular holder ring 62. As shown in FIG. 5, the surface of the holder ring 62 is covered with a seal ring 63 that is made of an elastic material, such as rubber. The seal ring 63 has an annular first seal portion 66. This first seal portion 66 is configured to be brought into pressure contact with a peripheral portion of the substrate W to thereby seal a gap between the holding member 58 and the substrate W. Further, the seal ring 63 has an annular second seal portion 68 on its surface facing the base member 54. The second seal portion 68 is configured to be brought into pressure contact with the base member 54 to thereby seal a gap between the base member 54 and the holding member 58.

The holder ring 62 has an annular stepped portion 70, and a retaining ring 64 is disposed below the stepped portion 70. The retaining ring 64 is rotatably mounted to a spacer 65. The retaining ring 64 is made of a material having high rigidity and excellent acid and alkali corrosion resistance. For example, the retaining ring 64 is made of titanium. The spacer 65 is made of a material, for example PTFE, having a low friction coefficient so that the retaining ring 64 can rotate smoothly.

At the outer side of the retaining ring 64, a plurality of clampers 74 are disposed at equal intervals along a circumferential direction of the retaining ring 64. The clampers 74 are secured to the base member 54. Each of the clampers 74 has an inverted L-shape having a projecting portion 74 a projecting inwardly. The retaining ring 64 has a plurality of projecting portions 64 a projecting outwardly. A lower surface of the projecting portion 74 a of the clamper 74 is configured to be in contact with an upper surface of the projecting portion 64 a of the retaining ring 64.

The lower surface of the projecting portion 74 a of the clamper 74 and the upper surface of the projecting portion 64 a of the retaining ring 64 have tapered surfaces respectively inclined in opposite directions along the rotational direction of the retaining ring 64. A plurality of (e.g., three) raised portions 64 b protruding upwardly are provided on the retaining ring 64 at predetermined positions along the circumferential direction of the retaining ring 64 (see FIG. 3). The retaining ring 64 can be rotated by pushing and rotating each raised portion 64 b in a lateral direction by means of a rotating pin (not shown).

With the holding member 58 open, the substrate W is inserted into the central portion of the base member 54, and the holding member 58 is then closed through the hinge 56. Subsequently, the retaining ring 64 is rotated clockwise so that each projecting portion 64 a of the retaining ring 64 slides into the inwardly projecting portion 74 a of each clamper 74. As a result, the base member 54 and the holding member 58 are fastened to each other to lock the holding member 58 by engagement between the tapered surfaces of the retaining ring 64 and the tapered surfaces of the clampers 74. The holding member 58 can be unlocked by rotating the retaining ring 64 counterclockwise to disengage the projecting portions 64 a of the retaining ring 64 from the clampers 74.

When the holding member 58 is locked, the first seal portion 66 is pressed against the peripheral portion of the substrate W. The first seal portion 66 is uniformly pressed against the substrate W to thereby seal the gap between the peripheral portion of the substrate W and the holding member 58. Similarly, when the holding member 58 is locked, the second seal portion 68 is pressed against the surface of the base member 54. The second seal portion 68 is uniformly pressed against the base member 54 to thereby seal the gap between the base member 54 and the holding member 58.

As shown in FIG. 3, a pair of holder hangers 108 is provided on an end portion of the base member 54 so as to project outwardly. Each holder hander 108 is constituted by an inner hanger portion 90 and an outer hanger portion 94. A hand lever 92 extends between the inner hanger portions 90 on both sides. In the processing bath 50, the substrate holder 8 is suspended from a surrounding wall of the bath through either the inner hanger portions 90 or the outer hanger portions 94 of the holder hanger 108.

A ring-shaped protrusion 82 having a size corresponding to a size of the substrate W is formed on the upper surface of the base member 54. The protrusion 82 has an annular support surface 80 that contacts the peripheral portion of the substrate W to support the substrate W. The protrusion 82 has recesses 84 arranged at predetermined positions along a circumferential direction of the protrusion 82.

As shown in FIG. 3, a plurality of (12 as illustrated) electrical conductors 86 are disposed in the recesses 84, respectively. These electrical conductors 86 are connected respectively to wires extending from a feeding terminal 91 provided on the holder hanger 108. As shown in FIG. 5, when the substrate W is loaded onto the substrate holder 8, end portions of the electrical conductors 86 are brought into resilient contact with electrical contacts 88 that are fixed to the holding member 58.

The electrical contact 88, which is electrically connected to the electrical conductor 86, has a plate spring shape. The electrical contact 88 has a contact portion located outside the first seal portion 66 and projecting inwardly in a plate spring shape. The electrical contact 88 has spring characteristics that can generate a resilient force and is configured to easily bend at the contact portion. When the substrate W is held between the base member 54 and the holding member 58, the contact portions of the electrical contacts 88 come into resilient contact with the peripheral portion of the substrate W that is supported on the support surface 80 of the base member 54.

When the first seal portion 66 is pressed against the substrate W and the second seal portion 68 is pressed against the base member 54, a hermetically closed space is formed along the peripheral portion of the substrate W. The electrical contacts 88 and the electrical conductors 86 are located in this hermetically closed space. Even if the substrate holder 8 is immersed in the plating solution, the plating solution does not enter the hermetically closed space of the substrate holder 8. Therefore, the substrate holder 8 can be used in the dip-type plating bath 34.

The holding member 58 is opened and closed by a not-shown pneumatic cylinder and by a weight of the holding member 58 itself. Specifically, the base member 54 has a through-hole 54 a, and a pneumatic cylinder (not shown) is provided in the opposite position of the through-hole 54 a. The holding member 58 is opened by pushing up the holder ring 62 of the holding member 58 with a piston rod of the pneumatic cylinder through the through-hole 54 a. The holding member 58 is closed by its own weight when the piston rod is retracted.

FIG. 6 is a schematic view showing the dip-type plating bath 34. As shown in FIG. 6, the dip-type plating bath 34 (hereinafter simply referred to as plating bath 34) is configured to be able to hold the first plating solution therein. An anode 71, held by an anode holder 72, is immersed in the first plating solution. The substrate holder 8, together with the substrate W, is immersed in the first plating solution held in the plating bath 34. Specifically, the holder hangers 108 of the substrate holder 8 are placed on a hanging base 129 on a pedestal 133 disposed on the plating bath 34, so that the substrate holder 8 is suspended in the plating bath 34. The anode 71 and the substrate W are disposed so as to face each other in the first plating solution. As described above, a copper plating solution, a nickel plating solution, or a solder plating solution may be used as the first plating solution held in the plating bath 34.

An overflow bath 99 is disposed around the plating bath 34, so that the first plating solution that has overflowed an upper edge of the plating bath 34 flows into the overflow bath 99. The first plating solution that has flowed into the overflow bath 99 is returned into the plating bath 34 through a circulation line (shown by arrow in FIG. 6).

In the vicinity of the surface of the substrate W held by the substrate holder 8 in the plating bath 34, there is disposed a paddle 100 as an agitating tool for agitating the first plating solution. The paddle 100 is vertically disposed and is configured to reciprocate in parallel to the substrate W to agitate the first plating solution, thereby uniformly supplying a sufficient amount of metal ions to the surface of the substrate W.

The anode 71 is electrically connected to a positive pole of a plating power source 75 via the anode holder 72, and the substrate W is electrically connected to a negative pole of the plating power source 75 via the substrate holder 8. By applying a voltage between the anode 71 and the substrate W, the substrate W is plated until a metal film is formed on the surface of the substrate W. While the substrate W is plated, the first plating solution circulates between the plating bath 34 and the overflow bath 99.

FIG. 7 is a schematic view showing the dry-type plating bath 35. As shown in FIG. 7, a holder cell 37 is disposed beside the dry-type plating bath 35 (hereinafter simply referred to as plating bath 35). The substrate holder 8 is transported by the transporter 101 into the holder cell 37. More specifically, the substrate holder 8 is transported to a predetermined position beside a sidewall 36 of the plating bath 35.

The plating bath 35 is configured to hold an electrolyte and the second plating solution therein. An anode 96 held by an anode holder 97 is immersed in the electrolyte. A plating solution may be used as the electrolyte. The anode 96 is kept immersed in the electrolyte in the plating bath 35 at all times. With such a configuration, a surface of the anode 96 is prevented from being deteriorated. Particularly, in a case where the anode 96 is made of copper, a black film formed on the surface of the anode 96 is prevented from being dried and falling, or being oxidized.

An overflow bath 127 is disposed adjacent to the plating bath 35. The electrolyte that has overflowed an upper edge of the plating bath 35 flows into the overflow bath 127. The electrolyte that has flowed into the overflow bath 127 is returned to the plating bath 35 by a pump through a circulation line.

The anode holder 97, holding the anode 96, is disposed at a predetermined position in the plating bath 35, and the substrate holder 8, holding the substrate W, is disposed at a predetermined position in the holder cell 37. The sidewall 36 of the plating bath 35 has a hole 36 a whose inner opening end is closed with a partition 107. The partition 107 has a structure that allows an electrical current to pass therethrough while not allowing a liquid to pass therethrough. The partition 107 is constituted by a porous material (e.g., ceramic, such as SiC (silicon carbide) or alumina), an ion exchange membrane, or the like. For example, in a case where a soluble anode is used as the anode 96, the ion exchange membrane is used as the partition 107. The partition 107 is disposed at a position facing the substrate W, and is located between the anode 96 and the substrate W.

In the holder cell 37, there is disposed a pressing mechanism 115 for moving the substrate holder 8 in a direction toward the sidewall 36 and in a direction away from the sidewall 36. The pressing mechanism 115 includes a suction pad 116 having a hollow 116 a and an actuator 118 for moving the suction pad 116. As the actuator 118, an annular tube, a pneumatic cylinder, a ball screw mechanism, or the like is used. The pressing mechanism 115 is configured to press the substrate holder 8 holding the substrate W against an outer surface of the sidewall 36, thereby closing an outer opening end of the hole 36 a, formed in the sidewall 36, with the substrate holder 8 holding the substrate W. In this state, a plating solution chamber 109 in which the second plating solution is present is formed between the substrate W and the partition 107.

In the sidewall 36 of the plating bath 35, there are provided delivery passages 112 a, 112 b and a plurality of communication passages 110 a, 110 b that provide fluid communication between the delivery passages 112 a, 112 b and the plating solution chamber 109. The second plating solution is supplied into the delivery passage 112 a and then supplied through the communication passage 110 a into the plating solution chamber 109. The second plating solution that has been introduced into the plating solution chamber 109 contacts a surface, to be plated, of the substrate W. The second plating solution that has contacted the substrate W is introduced through the communication passage 110 b into the delivery passage 112 b and then discharged from the delivery passage 112 b.

The discharged second plating solution is stored in a reservoir tank 113 through a discharge line 114. A supply line 119 for supplying the second plating solution to the delivery passage 112 a is connected to a lower part of the reservoir tank 113, and a pump P for delivering the second plating solution is mounted to the supply line 119. When the pump P is driven, the second plating solution in the reservoir tank 113 is returned to the delivery passage 112 a through the supply line 119. A recovery line 124 for recovering the second plating solution in the supply line 119 is connected to the supply line 119. More specifically, one end of the recovery line 124 is connected to the supply line 119, and the other end of the recovery line 124 is connected to the reservoir tank 113. An on-off valve 126 is attached to the recovery line 124. When the on-off valve 126 is opened, the second plating solution is delivered through the recovery line 124 into the reservoir tank 113. A drain valve 128 is attached to a lower part of the supply line 119. When the drain valve 128 is opened, the second plating solution is discharged to the exterior.

The second plating solution circulates through the circulation line as indicated by white arrow in FIG. 7. The width of the plating solution chamber 109, i.e., the distance between the substrate W and the partition 107, is short enough to cause the second plating solution on the surface of the substrate W to flow at a high velocity. Further, the direction in which the second plating solution flows may be switched to the opposite direction by a switching mechanism (not shown). The delivery passages 112 a, 112 b and the communication passages 110 a, 110 b may be arranged along the circumference of the substrate W so that the second plating solution flows in multiple patterns.

One surface of the partition 107 is in contact with the electrolyte and the other surface of the partition 107 is in contact with the second plating solution. As described above, the partition 107 allows the electrical current to pass therethrough but does not allow a liquid to pass therethrough. Thus, the partition 107 serves to isolate the second plating solution in the plating solution chamber 109 from the electrolyte in an electrolyte chamber 106.

FIG. 8 is a view showing a part of the substrate holder 8 pressed against the sidewall 36 of the dry-type plating bath 35. As shown in FIG. 8, the substrate holder 8 has an annular third seal portion 69 that is shaped so as to surround the outer opening end of the hole 36 a formed in the sidewall 36. When the substrate holder 8 is pressed against the sidewall 36, the third seal portion 69 is pressed against the outer surface of the sidewall 36 to seal a gap between the sidewall 36 and the holding member 58, thereby preventing the leakage of the second plating solution from the plating solution chamber 109. The first seal portion 66, the second seal portion 68, and the third seal portion 69 are formed from a single seal member (i.e., the seal ring 63).

Since the second plating solution is blocked by the third seal portion 69, the second plating solution hardly contacts the substrate holder 8. Therefore, an amount of the second plating solution attached to the substrate holder 8 can be minimized. Consequently, an amount of metal deposited on the substrate holder 8 can be reduced, and an amount of the second plating solution for replenishing the plating bath 35 can be reduced.

As described above, since the substrate holder 8 has the first seal portion 66, the second seal portion 68, and the third seal portion 69, the substrate holder 8 can be used both in the dip-type plating bath 34 and the dry-type plating bath 35. Therefore, it is not necessary to switch a substrate holder from one for use in the dip-type plating bath 34 to the other for use in the dry-type plating bath 35. As a result, the plating apparatus can perform multistage plating on the substrate W continuously.

As shown in FIG. 7, a tray 125 is disposed in a bottom of the holder cell 37, and the second plating solution that has leaked from the third seal portion 69 is discharged through a drain 125 a formed in the tray 125 to the exterior of the holder cell 37. In a case where the substrate holder 8 is not shared by the dip-type plating bath 34, i.e., in a case where the substrate holder 8 is used only in the dry-type plating bath 35, a drainage hole 117 communicating with the hermetically closed space may be provided in a bottom of the substrate holder 8, as shown in FIG. 9. With this configuration, even if the second plating solution enters the hermetically closed space of the substrate holder 8, the second plating solution is discharged through the drainage hole 117 to the exterior of the substrate holder 8.

The suction pad 116 is coupled to a vacuum source (not shown) that produces a vacuum in the hollow 116 a of the suction pad 116. With the substrate holder 8 held on the suction pad 116 via the vacuum suction, the actuator 118 moves the suction pad 116 in a direction away from the sidewall 36, thereby separating the substrate holder 8 from the sidewall 36.

The substrate holder 8 is transported into the holder cell 37 by the transporter 101. The holder hangers 108 are placed on a hanging base 120 on a pedestal 121 disposed on the holder cell 37, so that the substrate holder 8 is suspended in the holder cell 37.

FIG. 10A is a view showing the substrate holder 8 when hanging from the hanging base 120. As shown in FIG. 10A, the hanging base 120 has an electrical contact 122 that is electrically connected to a plating power source 98. The substrate holder 8 is placed on the hanging base 120 to hang from the hanging base 120, and then the pressing mechanism 115 presses the substrate holder 8 against the sidewall 36. While the pressing mechanism 115 presses the substrate holder 8 against the sidewall 36 to close the hole 36 a with the substrate holder 8 holding the substrate W, the pressing mechanism 115, at the same time, presses the feeding terminal 91 of the substrate holder 8 against the electrical contact 122.

FIG. 10B is a view showing the substrate holder 8 with its feeding terminal 91 pressed against the electrical contact 122. As shown in FIG. 10B, the feeding terminal 91 is brought into contact with the electrical contact 122, thereby electrically connecting the substrate W to a negative pole of the plating power source 98 via the substrate holder 8. A sliding member 123 for enabling the substrate holder 8 to move smoothly is provided on the hanging base 120. This sliding member 123 is made of a material having a low coefficient of friction. The feeding terminal 91 is preferably a resilient member that is brought into resilient contact with the electrical contact 122.

FIG. 11A is a view showing the substrate holder 8 before hanging from the hanging base 120 of the dip-type plating bath 34. FIG. 11B is a view showing the substrate holder 8 when hanging from the hanging base 120. As shown in FIGS. 11A and 11B, in the case where the substrate holder 8 is used in the dip-type plating bath 34, the substrate holder 8 is moved in the direction shown by arrow until the holder hanger 108 is inserted into the hanging base 120. As a result of this movement, the feeding terminal 91 is brought into contact with the electrical contact 122. In this case, since it is not necessary to slide the substrate holder 8 in a lateral direction, the sliding member 123 needs not to be provided on the hanging base 120.

FIGS. 12A and 12B show another embodiment of hanging base 120 used in the dip-type plating bath 34. More specifically, FIG. 12A is a view showing the substrate holder 8 before hanging from the hanging base 120 having an electrical contact 132 provided on an upper surface of the hanging base 120. FIG. 12B is a view showing the substrate holder 8 when hanging from the hanging base 120 shown in FIG. 12A. As shown in FIGS. 12A and 12B, in addition to the feeding terminal 91 provided on a side surface of the holder hanger 108, a feeding terminal 131 may be provided on a bottom surface of the holder hanger 108 and the electric contact 132 may be provided on the upper surface of the hanging base 120. More specifically, the holder hanger 108 of the substrate holder 8 may be provided with both of the feeding terminal 131 for the dip-type plating bath 34 and the feeding terminal 91 for the dry-type plating bath 35. As shown in FIG. 12B, when the substrate holder 8 is used in the dip-type plating bath 34, the feeding terminal 131 is brought into contact with the electrical contact 132. Since the holder hanger 108 of the substrate holder 8 is provided with the feeding terminals respectively for the dip-type plating bath 34 and the dry-type plating bath 35, these feeding terminals are allowed to have shapes and materials suitable for current densities used in the respective plating baths.

The substrate W is plated as follows. The substrate holder 8 holding the substrate W is transported into the holder cell 37. The pressing mechanism 115 presses the substrate holder, holding the substrate W, against the sidewall 36 of the plating bath 35 to close the outer opening end of the hole 36 a with the substrate holder 8 holding the substrate W and, at the same time, presses the feeding terminal 91 of the substrate holder 8 against the electrical contact 122. The gap between the holding member 58 and the sidewall 36 of the plating bath 35 is sealed with the third seal portion 69. The second plating solution is supplied to the plating solution chamber 109 through the delivery passage 112 a and the communication passage 110 a to contact the surface, to be plated, of the substrate W. In this state, a voltage is applied between the substrate W and the anode 96 by the plating power source 98, whereby the substrate W is plated.

After the plating of the substrate W is completed, the supply of the second plating solution to the plating solution chamber 109 is stopped. Then, the on-off valve 126 is opened to recover the second plating solution from the plating solution chamber 109 through the recovery line 124. Thereafter, the pressing mechanism 115 is operated so as to separate the substrate holder 8 from the sidewall 36 of the plating bath 35. The substrate holder 8 is then removed from the holder cell 37 by the transporter 101.

When the substrate W is plated with use of the plating bath 35 discussed above, the plating solution may be attached to the sidewall 36 that contacts the substrate holder 8. As a result, a metal may be deposited on the sidewall 36, possibly causing the leakage of the second plating solution from a gap between the sidewall 36 and the third seal portion 69 of the substrate holder 8. In order to prevent such metal deposition, it is necessary to clean the sidewall 36. A possible way of cleaning the sidewall 36 includes the step of ejecting a cleaning liquid directly toward the sidewall 36. However, it is difficult for the jet of the cleaning liquid to remove the deposited metal. Thus, the plating apparatus according to the embodiment includes a cleaning device 140 that can remove the deposited metal.

FIG. 13 is a plan view showing the cleaning device 140, and FIG. 14 is a cross-sectional view of the cleaning device 140. As shown in FIGS. 13 and 14, the cleaning device 140 includes an annular cleaning element 142 that is to be brought into contact with the sidewall 36, a circular movable member 145 that holds the cleaning element 142, a bearing 144 that rotatably supports the movable member 145, and a rotating mechanism 143 for rotating the movable member 145 and the cleaning element 142. As the cleaning element 142, a non-woven fabric, a PVA sponge, or the like may be used. The rotating mechanism 143 and the bearing 144 are fixed to a frame 141. A pair of hangers 146 is provided on an end portion of the frame 141 so as to project outwardly. The bearing 144 is made of a corrosion-resistant material, such as resin or ceramic. The cleaning device 140 may further include a cleaning nozzle 155 for ejecting a cleaning liquid toward the cleaning element 142. The cleaning nozzle 155 is disposed above the cleaning element 142 and ejects the cleaning liquid toward the cleaning element 142 or a contact area of the cleaning element 142 and the sidewall 36, thereby wetting the cleaning element 142.

The rotating mechanism 143 includes a pneumatic cylinder 150 and a linkage mechanism 151 for transmitting the movement of the pneumatic cylinder 150 to the movable member 145. The linkage mechanism 151 includes a first link 151 a coupled to a piston rod 150 a of the pneumatic cylinder 150, and a second link 151 b fixed to the movable member 145. Instead of a combination of the pneumatic cylinder 150 and the linkage mechanism 151, a rack-and-pinion may be used as the rotating mechanism 143. As shown in FIG. 14, one end of the second link 151 b is coupled to the first link 151 a, and the other end of the second link 151 b is fixed to the movable member 145.

The rotating mechanism 143 further includes two gas delivery conduits 152A, 152B for actuating the pneumatic cylinder 150. The pneumatic cylinder 150 is connected to the gas delivery conduits 152A, 152B, which are coupled to a gas supply source (not shown).

When a gas is supplied into the pneumatic cylinder 150 through the gas delivery conduit 152A, the piston rod 150 a extends to rotate the cleaning element 142 and the movable member 145 through a certain angle in a counterclockwise direction. When the gas is supplied into the pneumatic cylinder 150 through the gas delivery conduit 152B, the piston rod 150 a retracts to rotate the cleaning element 142 and the movable member 145 through the certain angle in a clockwise direction. By repeating such operations of the pneumatic cylinder 150, the cleaning element 142 is rotated through the certain angle in the clockwise direction and the counterclockwise direction alternately. In other words, the cleaning element 142 oscillates in its circumferential direction. The rotating mechanism 143 may employ a combination of a motor and gears to completely rotate the cleaning element 142 in one direction.

FIG. 15 is a schematic view showing the cleaning device 140 pressed against the sidewall 36 of the plating bath 35. As shown in FIG. 15, the cleaning nozzle 155 may be provided on the dry-type plating bath 35 instead of the cleaning device 140. The cleaning nozzle 155 is provided above the plating bath 35, i.e., on the pedestal 121. The cleaning nozzle 155 is configured to supply the cleaning liquid widely toward the cleaning device 140 (cleaning element 142) located obliquely downwardly from the cleaning nozzle 155. A fan-shaped nozzle or the like may be used as the cleaning nozzle 155. When the cleaning device 140 is being transported into the holder cell 37, the cleaning nozzle 155 ejects the cleaning liquid to the cleaning element 142 to wet the cleaning element 142. The cleaning nozzle 155 may continuously eject the cleaning liquid to the cleaning element 142 during cleaning of the sidewall 36 as well.

As shown in FIG. 14, a drainage hole 156 is formed in a bottom of the frame 141. The cleaning liquid that has entered a gap between the movable member 145 and the frame 141 is discharged through the drainage hole 156 to the exterior of the cleaning device 140. Further, the cleaning liquid is discharged through the drain 125 a of the holder cell 37 to the exterior of the holder cell 37.

The cleaning device 140 has substantially the same shape and size as those of the substrate holder 8. Therefore, the transporter 101 can transport the cleaning device 140, as with the substrate holder 8, to a predetermined position beside the sidewall 36 of the dry-type plating bath 35. Specifically, the cleaning device 140 is transported to a predetermined position in the holder cell 37 by the transporter 101. The hangers 146 of the cleaning device 140 are placed on the hanging base 120 so that the cleaning device 140 hangs from the hanging base 120. The cleaning device 140 is then pressed against the sidewall 36 by the pressing mechanism 115. The cleaning device 140 is pressed by the pressing mechanism 115 under an appropriate contact surface pressure that does not cause the sidewall 36 to wear. A surface treatment may be applied to the sidewall 36 so as to impart wear resistance to the sidewall 36.

As shown in FIG. 15, the pressing mechanism 115 presses the cleaning device 140 against the sidewall 36 of the plating bath 35 to bring the cleaning element 142 into contact with the sidewall 36. The area where the cleaning element 142 is in contact is an area around the outer opening end of the hole 36 a formed in the sidewall 36.

The cleaning nozzle 155 supplies the cleaning liquid to a contact area of the cleaning element 142 and the sidewall 36 to wet the cleaning element 142. In this state, the cleaning element 142 is rotated on the sidewall 36 by the rotating mechanism 143 to remove the metal deposited on the sidewall 36. The cleaning element 142 is removably held by the movable member 145 so that the cleaning element 142 can be exchanged with a new cleaning element.

If the cleaning device 140 is pressed against the sidewall 36 with a force equal to a force with which the pressing mechanism 115 presses the substrate holder 8 against the sidewall 36, the cleaning element 142 may not rotate smoothly, thus possibly damaging the surface of the sidewall 36. In order to prevent this, as shown in FIGS. 13 and 14, the cleaning device 140 may include pressing-force regulators 160 for regulating the pressing force with which the cleaning element 142 is pressed against the sidewall 36. As shown in FIG. 14, each pressing-force regulator 160 includes a protruding element 163 housed in a housing aperture 161 formed in the frame 141 and a biasing member 162 for biasing the protruding element 163. The biasing member 162 comprises an expandable member, such as a spring, to bias the protruding element 163 in a direction as to press the protruding element 163 against the sidewall 36.

The pressing-force regulators 160 are arranged on the frame 141 at a plurality of (four in FIG. 13) positions along the circumferential direction of the cleaning element 142. The cleaning device 140 is pressed from a back side thereof by the pressing mechanism 115 so that the cleaning element 142 is pressed against the area surrounding the outer opening end of the hole 36 a of the sidewall 36. At this time, the protruding elements 163 of the pressing-force regulators 160 are brought into contact with the sidewall 36 to be retracted, thus receiving a part of the pressing force of the pressing mechanism 115. As a result, the cleaning element 142 is in contact with the sidewall 36 at the appropriate contact surface pressure and can therefore rotate smoothly.

As another mechanism of regulating the force of pressing the cleaning device 140 against the sidewall 36, the pressing force of the actuator 118 may be regulated. For example, in the case where the actuator 118 comprises a pneumatic cylinder, a working-air line may be switched to a different working-air line in which a working-air pressure is regulated by a precision pressure regulating valve, so that the pressing force of the pneumatic cylinder can be reduced.

As described above, since the cleaning device 140 has substantially the same shape and size as those of the substrate holder 8, the transporter 101 can transport the cleaning device 140, as with the substrate holder 8, to the holder cell 37 that is adjacent to the dry-type plating bath 35 and can set the cleaning device 140, as with the substrate holder 8, to the predetermined position in the holder cell 37. Therefore, the cleaning device 140 can clean the sidewall 36 without stopping the operation of the plating apparatus. The cleaning device 140 is stored in the storage container 30 in advance, and is removed from the storage container 30 by the transporter 101 as necessary. While the plating apparatus is being operated, the cleaning device 140 can continuously clean the sidewall 36 of the dry-type plating bath 35 when it is not in use. The cleaning device 140 is cleaned in the third rinsing bath 42. A dedicated rinsing bath for cleaning the cleaning device 140 may be separately provided.

Next, the operation of the plating apparatus in its entirety will be described. First, the substrate holder 8 in a vertical position is taken out from the storage container 30 by the arm 104 of the transporter 101. The arm 104, gripping the substrate holder 8, is moved in the horizontal direction to transfer the substrate holder 8 to the substrate holder opening-closing mechanism 24. The substrate holder opening-closing mechanism 24 changes the substrate holder 8 from the vertical position to the horizontal position, and opens the substrate holder 8.

The substrate transfer robot 22 takes out a substrate W from the cassette mounted to the load port 2 and places the substrate W on the aligner 4. The aligner 4 aligns the position of an orientation flat or a notch of the substrate W with a predetermined direction. The substrate transfer robot 22 removes the substrate W from the aligner 4 and inserts the substrate W into the substrate holder 8. In this state, the substrate holder opening-closing mechanism 24 closes the substrate holder 8 to lock the substrate holder 8.

Next, the substrate holder opening-closing mechanism 24 changes the substrate holder 8 from the horizontal position to the vertical position. The gripper 111 of the arm 104 grips the substrate holder 8 that is in the vertical position and moves the substrate holder 8 in the horizontal direction to a position above the pre-cleaning bath 32. The lifter 103 of the transporter 101 then lowers the arm 104, together with the substrate holder 8, to set the substrate holder 8 at a predetermined position in the pre-cleaning bath 32. In this state, the substrate W is pre-cleaned. After the pre-cleaning of the substrate W is completed, the gripper 111 of the arm 104 grips the substrate holder 8, and the lifter 103 lifts the arm 104 to raise the substrate holder 8 from the pre-cleaning bath 32.

Then, the arm 104 moves the substrate holder 8 in the horizontal direction to a position above the pretreatment bath 33. The lifter 103 lowers the arm 104, together with the substrate holder 8, to set the substrate holder 8 at a predetermined position in the pretreatment bath 33. In this state, the substrate W is pretreated. After the pretreatment of the substrate W is completed, the gripper 111 of the arm 104 grips the substrate holder 8, and the lifter 103 lifts the arm 104 to raise the substrate holder 8 from the pretreatment bath 33. Thereafter, the arm 104 moves the substrate holder 8 in the horizontal direction to a position above the first rinsing bath 40. The lifter 103 lowers the arm 104, together with the substrate holder 8, to set the substrate holder 8 at a predetermined position in the first rinsing bath 40. In this state, the substrate W is rinsed. After the rinsing of the substrate W is completed, the gripper 111 of the arm 104 grips the substrate holder 8, and the lifter 103 lifts the arm 104 to raise the substrate holder 8 from the first rinsing bath 40.

The arm 104 moves the substrate holder 8 in the horizontal direction to a position above the dip-type plating bath 34. Further, the lifter 103 of the transporter 101 lowers the arm 104, together with the substrate holder 8, to set the substrate holder 8 at a predetermined position in the dip-type plating bath 34. The substrate holder 8, together with the substrate W, is immersed in the plating solution. Thereafter, the substrate W is plated. Since the substrate holder 8 has the first seal portion 66 and the second seal portion 68, the plating solution does not enter the substrate holder 8. After the plating of the substrate W is completed, the gripper 111 of the arm 104 grips the substrate holder 8, and the lifter 103 lifts the arm 104 to raise the substrate holder 8 from the dip-type plating bath 34.

The arm 104 moves the substrate holder 8 in the horizontal direction to a position above the second rinsing bath 41. Further, the lifter 103 lowers the arm 104, together with the substrate holder 8, to set the substrate holder 8 at a predetermined position in the second rinsing bath 41. In this state, the plated substrate W is rinsed. After the rinsing of the substrate W is completed, the gripper 111 of the arm 104 grips the substrate holder 8, and the lifter 103 lifts the arm 104 to raise the substrate holder 8 from the second rinsing bath 41.

The arm 104 moves the substrate holder 8 in the horizontal direction to a position above the holder cell 37 adjacent to the plating bath 35. The lifter 103 lowers the arm 104, together with the substrate holder 8, to set the substrate holder 8 at a predetermined position in the holder cell 37. The pressing mechanism 115 presses the substrate holder 8 against the sidewall 36, thereby placing the substrate holder 8 in tight contact with the sidewall 36. In this state, the second plating solution is supplied into the plating solution chamber 109. Then, the substrate W is plated by applying the voltage between the anode 96 and the substrate W. Since the substrate holder 8 has the third seal portion 69, the second plating solution does not leak from the plating bath 35 during the plating of the substrate W.

After the plating of the substrate W is completed, the supply of the second plating solution into the plating solution chamber 109 is stopped, and the second plating solution is discharged from the plating solution chamber 109. When the vacuum is created in the hollow 116 a of the suction pad 116, the suction pad 116 holds the substrate holder 8 by the vacuum suction and, in this state, the pressing mechanism 115 separates the substrate holder 8 from the sidewall 36. Thereafter, the vacuum in the hollow 116 a is broken, and the lifter 103 lifts the arm 104 to raise the substrate holder 8 from the holder cell 37.

The arm 104 moves the substrate holder 8 in the horizontal direction to a position above the third rinsing bath 42. Further, the lifter 103 of the transporter 101 lowers the arm 104, together with the substrate holder 8, to set the substrate holder 8 at a predetermined position in the third rinsing bath 42. In this state, rinsing of the plated substrate W is performed. After the rinsing of the substrate W is completed, the gripper 111 of the arm 104 grips the substrate holder 8, and the lifter 103 lifts the arm 104 to raise the substrate holder 8 from the third rinsing bath 42.

The arm 104 moves the substrate holder 8 in the horizontal direction to a position above the blow cell 38. Further, the lifter 103 lowers the arm 104, together with the substrate holder 8, to set the substrate holder 8 at a predetermined position in the blow cell 38. In the blow cell 38, a jet of N₂ gas or clean air is supplied onto the substrate holder 8 so as to remove droplets attached to the surface of the substrate W held by the substrate holder 8, thereby drying the substrate W. After the blow process is completed, the gripper 111 of the arm 104 grips the substrate holder 8, and the lifter 103 lifts the arm 104 to raise the substrate holder 8 from the blow cell 38.

The arm 104 moves in the horizontal direction to transfer the substrate holder 8 to the substrate holder opening-closing mechanism 24. The substrate holder opening-closing mechanism 24 opens the substrate holder 8 in the previously-described manner. The substrate transfer robot 22 removes the processed substrate W from the substrate holder 8 and then transfers the substrate W to the spin-rinse dryer 6. The spin-rinse dryer 6 rotates the substrate W at a high speed to dry the substrate W. The substrate transfer robot 22 removes the dried substrate W from the spin-rinse dryer 6 and returns the substrate W to the cassette on the load port 2. In this manner, the process of the substrate W is completed.

FIG. 16 is a view comparing the length of the plating apparatus according to the embodiment to the length of a typical dry-type plating apparatus. The plating apparatus according to the embodiment is shorter by length L than that of the typical dry-type plating apparatus. The typical dry-type plating apparatus includes seven dry-type plating baths 35. In contrast, the plating apparatus according to the embodiment includes five dip-type plating baths 34 and two dry-type plating baths 35. Since the plating apparatus according to the embodiment includes the dry-type plating baths 35 and the dip-type plating baths 34, the plating solution remaining on the substrate holder 8 can be reduced without enlarging the footprint of the plating apparatus.

FIG. 17 is a view showing a modified embodiment of dry-type plating bath 35. Partition 107 is held by a partition holder 139 disposed in the plating bath 35. The interior of the plating bath 35 is partitioned into electrolyte chamber 106 and plating solution chamber 109 by the partition 107. In the plating solution chamber 109, there is disposed a paddle 130 for agitating the second plating solution. The paddle 130 is vertically disposed and is configured to reciprocate in parallel with the substrate W so as to agitate the second plating solution.

Sidewall 36 of the plating bath 35 has hole 36 a for allowing the surface, to be plated, of the substrate W to contact the second plating solution in the plating solution chamber 109. The substrate holder 8, holding the substrate W, is pressed against the sidewall 36 of the plating bath 35 by the pressing mechanism 115 to close the hole 36 a with the substrate holder 8 holding the substrate W. In this state, the second plating solution is supplied into the plating solution chamber 109 to contact the surface, to be plated, of the substrate W. Then, a voltage is applied between the substrate W and anode 96 to thereby plate the substrate W. While the substrate W is being plated, the second plating solution circulates between an overflow bath (not shown) and the plating solution chamber 109. Specifically, the second plating solution overflows the plating solution chamber 109 into the overflow bath (not shown) and is returned into the plating solution chamber 109.

In the case where the substrate holder 8 is not shared by the dip-type plating bath 34, i.e., in the case where the substrate holder 8 is used only in the plating bath 35, as shown in FIG. 18, the drainage hole 117 communicating with the above-described hermetically closed space may be provided in the bottom of the substrate holder 8. With this configuration, even if the second plating solution enters the hermetically closed space of the substrate holder 8, the second plating solution is discharged through the drainage hole 117 to the exterior of the substrate holder 8.

FIG. 19 is an enlarged view showing a part enclosed by a symbol A shown in FIG. 17. The substrate holder 8 has a projecting surface (i.e., a surface 63 a of the seal ring 63) projecting in the normal direction of the substrate W, and stepped portion 70 at the outside of the projecting surface 63 a. When the pressing mechanism 115 presses the substrate holder 8 against the sidewall 36, a portion of holder ring 62 lying at an inner side of the annular stepped portion 70 is inserted into the hole 36 a. In this state, the annular stepped portion 70 extends so as to surround the outer opening end of the hole 36 a. The substrate holder 8 has third seal portion 69 on the stepped portion 70. When the substrate holder 8 is pressed against the sidewall 36 by the pressing mechanism 115, the third seal portion 69 on the stepped portion 70 is brought into contact with the sidewall 36. The third seal portion 69 is pressed against the outer surface 36 b of the sidewall 36 to seal a gap between the sidewall 36 and the holding member 58 of the substrate holder 8.

In the embodiment shown in FIGS. 5 and 8, the third seal portion 69 constitutes the most projecting surface, of the holding member 58, projecting in the normal direction of the substrate W. However, in the embodiment shown in FIG. 19, the third seal portion 69 is provided on the stepped portion 70. The first seal portion 66, the second seal portion 68, and the third seal portion 69 constitute the integrally-formed seal ring 63 made of an elastic material, such as rubber. The seal ring 63 shown in FIG. 19 has the same structure as the seal ring 63 shown in FIGS. 5 and 8. Specifically, when the substrate holder 8 is used in the plating bath 35 shown in FIG. 7, the portion of the seal ring 63 that constitutes the most projecting surface of the substrate holder 8 serves as the third seal portion 69, and when the substrate holder 8 is used in the plating bath 35 shown in FIG. 17, the portion of the seal ring 63 provided on the stepped portion 70 of the holder ring 62 serves as the third seal portion 69.

In order to agitate the plating solution in the vicinity of the surface of the substrate W, the paddle 130 is preferably disposed as close to the surface of the substrate W as possible. Therefore, when the substrate holder 8 is pressed against the sidewall 36, the most projecting surface of the substrate holder 8, i.e., the surface 63 a of the seal ring 63, preferably lies in the same plane as an inner surface 36 c of the sidewall 36. With such a configuration, the paddle 130 can be disposed closer to the surface, to be plated, of the substrate W. Alternatively, the surface 63 a of the seal ring 63 may project from the inner surface 36 c of the sidewall 36 toward the plating solution chamber so that the paddle 130 can be disposed even closer to the surface, to be plated, of the substrate W.

The above-discussed cleaning device 140 can also be used in the dry-type plating bath 35 shown in FIG. 17.

The previous description of embodiments is provided to enable a person skilled in the art to make and use the present invention. Moreover, various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles and specific examples defined herein may be applied to other embodiments. Therefore, the present invention is not intended to be limited to the embodiments described herein but is to be accorded the widest scope as defined by limitation of the claims and equivalents. 

What is claimed is:
 1. A plating apparatus for plating a substrate, comprising: a substrate holder configured to hold the substrate; a dip-type plating bath configured to hold a first plating solution in which the substrate holder holding the substrate is immersed; a dry-type plating bath having a hole in a sidewall thereof and configured to hold a second plating solution; a transporter configured to transport the substrate holder to the dip-type plating bath and to a predetermined position beside the sidewall of the dry-type plating bath; and a pressing mechanism configured to press the substrate holder, holding the substrate, against the sidewall of the dry-type plating bath to thereby close the hole with the substrate holder holding the substrate, wherein the substrate holder includes a base member and a holding member configured to sandwich the substrate therebetween, a first seal portion configured to seal a gap between the substrate and the holding member, a second seal portion configured to seal a gap between the base member and the holding member, and a third seal portion configured to seal a gap between the holding member and the sidewall of the dry-type plating bath.
 2. The plating apparatus according to claim 1, further comprising an electrical contact electrically connected to a plating power source, wherein the substrate holder includes a feeding terminal to be electrically connected to the substrate, and wherein the pressing mechanism is configured to press the substrate holder, holding the substrate, against the sidewall of the dry-type plating bath to close the hole with the substrate holder holding the substrate while pressing the feeding terminal against the electrical contact.
 3. The plating apparatus according to claim 1, wherein: the substrate holder includes a projecting surface projecting in a normal direction of the substrate, and a stepped portion provided outside of the projecting surface; and the third seal portion is provided on the stepped portion so that the third seal portion is pressed against the sidewall by the pressing mechanism.
 4. The plating apparatus according to claim 3, wherein the projecting surface of the substrate holder lies in the same plane as an inner surface of the sidewall when the substrate holder is pressed against the sidewall.
 5. The plating apparatus according to claim 1, wherein the first seal portion, the second seal portion, and the third seal portion are formed from a single seal member.
 6. The plating apparatus according to claim 1, wherein: the dry-type plating bath has an electrolyte chamber configured to hold an electrolyte, and a partition configured to isolate the second plating solution from the electrolyte; and an anode is disposed in the electrolyte chamber.
 7. The plating apparatus according to claim 1, further comprising a cleaning device configured to clean the sidewall of the dry-type plating bath, wherein the cleaning device has substantially the same shape and size as those of the substrate holder, and wherein the transporter is configured to transport the cleaning device to the predetermined position beside the sidewall of the dry-type plating bath.
 8. The plating apparatus according to claim 7, wherein the cleaning device includes a cleaning element configured to contact the sidewall of the dry-type plating bath, and a rotating mechanism configured to rotate the cleaning element on the sidewall.
 9. The plating apparatus according to claim 8, further comprising a cleaning nozzle configured to supply a cleaning liquid to the cleaning element.
 10. The plating apparatus according to claim 1, wherein the second plating solution comprises a gold plating solution.
 11. A cleaning device for use in a plating apparatus that includes (i) a substrate holder configured to hold a substrate, (ii) a dry-type plating bath having a hole in a sidewall thereof and configured to hold a plating solution, and (iii) a pressing mechanism configured to press the substrate holder, holding the substrate, against the sidewall of the dry-type plating bath to thereby close the hole with the substrate holder holding the substrate, the cleaning device comprising: a cleaning element configured to contact the sidewall of the dry-type plating bath; and a rotating mechanism configured to rotate the cleaning element on the sidewall of the dry-type plating bath, wherein the cleaning device has substantially the same shape and size as those of the substrate holder.
 12. The cleaning device according to claim 11, further comprising a cleaning nozzle configured to supply a cleaning liquid to the cleaning element. 